1. Field
The present invention relates to computerized medical simulation in general, and more specifically to virtual reality and/or augmented reality simulation devices and systems for medical training purposes.
2. Technical Background
Traditional medical procedures requiring invasive surgery are frequently being replaced by less invasive image-guided techniques taking advantage of modern imaging technologies, such as endoscopy, for both diagnostic and therapeutic purposes. These new techniques may require dedicated training for physicians and surgeons to master the indirect hand-eye coordination required by the imaging system as well as the manipulation of the imaging tools in addition to the conventional medical instruments and procedures. Computerized medical procedure training simulators may enable the physicians and trainees to develop and improve their practice in a virtual reality environment before actually practicing in the operation room.
Advanced medical procedure simulators may be based on a virtual reality (“VR”) and/or a mixed or augmented reality (“AR”) simulation apparatus by which the physician can experiment a medical procedure scenario. The VR/AR system may compute and display a visual VR/AR model of anatomical structures in accordance with physician gestures and actions to provide various feedback, such as visual feedback. In a VR system, an entire image may be simulated for display to a user, and in an AR system, a simulated image may be overlaid or otherwise incorporated with an actual image for display to a user. Various patient models with different pathologies can be selected. Therefore, natural variations as encountered over the years by practicing surgeons can be simulated for a user over a compressed period of time for training purposes. The medical simulation procedure can be recorded and rehearsed for evaluation purpose. The VR/AR simulation system can also compute and provide various metrics and statistics.
Some VR/AR simulation systems such as the one described in patent application US2010/0086905 include a human anatomy model of a joint of organ in real size and a simulated medical instrument that imitates the real medical procedure instrument. The model is further adapted with sensors and mobile members for guiding, tracking and controlling the medical instrument operation within the anatomy model. The simulated medical instrument is usually adapted from dedicated VR or AR hardware to provide haptic feedback, such as force feedback, to the physician to reproduce the instrument touch and feel sensing when touching the model.
Legacy medical VR/AR simulators often require dedicated haptic hardware such as, for instance, the two haptic devices arranged with a mobile member in the arthroscopy VR simulator described in U.S. patent application 2010/0086905. Those VR/AR simulators can require specific setup and calibration prior to be operated; they can be expensive; they may suffer a number of mechanical constraints, such as friction, and the maximal amount of forces and torques displayed may be insufficient to provide a realistic simulation. The degree of possible motion of the tools due to mechanical configuration of the device can be limited. Moreover, the setup can be unstable over time, thus requiring regular maintenance to avoid inducing training errors. Furthermore, for a multipurpose training room, many simulators may be required, as different anatomical features may require different simulators. For instance, a knee arthroscopy simulator and a pelvic simulator may require two different simulators to be set up and calibrated. Furthermore, in order to align a VR/AR computerized simulation visual feedback to an actual physical gesture and action of the simulation tools, the VR/AR system may require a calibration setup phase to position the VR/AR model relative to real world position and orientation of each simulated instrument before the simulator becomes operational. Wrong calibration should be carefully avoided as it can be a source of significant training errors, potentially harmful to patients in later real operations. As taught for instance by U.S. patent application 2010/0248200, the haptic device is therefore often manually calibrated by asking one or more experienced physician or medical residents to touch all virtual tissues using a virtual medical procedural tool, which may for example be a virtual blade, controlled by the haptic device.
The training tools described above can create significant budget and time overhead for the multipurpose training room operation, as multiple dedicated hardware devices may need to be installed in the room and skilled personnel may be required to operate the devices. Switching from one medical training procedure to another may be consequently cumbersome and time-consuming.